Because of the wide-open nature of the feeding throat associated with balers of this type, in certain conditions there may be a tendency for the belts which coil up and pack the crop material to eject such material back out of the chamber through the open throat instead of coiling it up in the proper manner. This is particularly true in short, light crop materials such as wheat straw.
However, the benefits obtained through an open throat design, as opposed to a closed or constricted throat configuration in which a pair of compression or nip rollers are utilized, are so significant that it is desirable to maintain the unobstructed and unconstricted flow of materials into the baling chamber while somehow eliminating the retrograde flow or ejection action above referred to.